/*
 * Copyright (c) 2016, 2021, Oracle and/or its affiliates.
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification, are
 * permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this list of
 * conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice, this list of
 * conditions and the following disclaimer in the documentation and/or other materials provided
 * with the distribution.
 *
 * 3. Neither the name of the copyright holder nor the names of its contributors may be used to
 * endorse or promote products derived from this software without specific prior written
 * permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS
 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
 * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 */
#include <stdio.h>
#include <string.h>

int main() {
    unsigned char buf[16];
    unsigned long out;
    unsigned int i;

    printf("Writing %zu elements of value %d (byte %d)\n", sizeof(buf), 0xCC, (char) 0xCC);

    memset(buf, 0xCC, sizeof(buf));
    printf("buf (before):");
    for (i = 0; i < 16; i++)
        printf(" %02X", buf[i]);
    printf("\n");

    __asm__("cld\n"
            "lea %1, %%rdi\n"
            "movb $0x42, %%al\n"
            "movq $10, %%rcx\n"
            "rep stosb\n"
            "movq %%rdi, %0"
            : "=r"(out)
            : "m"(buf[2])
            : "rax", "rcx", "rdi");

    printf("buf (after): ");
    for (i = 0; i < 16; i++)
        printf(" %02X", buf[i]);
    printf("\n");

    return (out == ((unsigned long) &buf[12]));
}
